1. Field of the Invention
The invention relates to a cooler for combustible material, which in a first section is traversed by cooling air to be fed completely to the burner as air for combustion, and has a further section likewise traversed by cooling air under the effect of at least one blower or ventilator.
2. Prior Art
In a known cooler type, as seen in the Germany petty patent ("Gebrauchsmuster") No. 1,985,673, issued to the firm of Polysius G.m.b.H., of Neubechum, an air-traversed water screen is divided into two sections. The cooling air flowing through the first section is fed to the calcining furnace as additional air for combustion, while the cooling air of the second section is passed as exhaust air over the roof. A waste heat utilization of the exhaust air of the second cooler section is profitable generally only when the exhaust heat can be utilized directly, e.g., for a warming-up or drying of the material to be fed to the burner. It cannot be used for current generation since with the relatively low exhaust air temperatures and the expense necessary for its dust removal, the efficiency is too low and thereby the energy cost becomes too high. This applies also to another known cooler type, as disclosed by Kayatz in U.S. Pat. No. 3,705,620, which provides an indirect cooling in the second stage. In such a case, to be sure, the expense for the dust removal from the cooling air is eliminated. However, with indirect cooling air, the cooling air is of a lower temperature, which decreases further the efficiency of a transformation of energy.